1. Field of the Invention
The present invention relates to means for obtaining an image from a sheet-like member by producing light within the member. The light so produced is attenuated by images on the surface thereof to provide means for copying the image.
2. Discussion of the Prior Art
In a conventional copying machine the image bearing surface of the original must be illuminated in order to facilitate the copying operation. This is conventionally done by a lamp and lens system but such devices are bulky, expensive and consume large amounts of electrical power.
A conventional copying machine, having a contact exposure system in which an original's surface is placed near or in contact with a photosensitive surface, uses contact transmission-type exposure. In such devices the original's surface is placed in contact with a photosensitive surface, while the other surface of the original is illuminated by illuminating means such as a lamp. Light passes through the original and is applied to the photosensitive surface. Alternatively, in such a contact exposure-type device, the original's surface may be kept in close contact with a photosensitive unit and the photosensitive unit is illuminated by illuminating means such as a lamp. Light reflected from the original's surface is applied to the photosensitive surface.
Such devices need, not only a lamp to illuminate an original's surface, but also a device for controlling the lamp.
Where it is required to copy, and therefore illuminate, both sides of an original, it is necessary for the operator to manually turn over the original or mechanical means for turning over an original must be provided. The first alternative requires a machine operator whose efficiency is reduced by the need to turn over the original and the second, a complex mechanical system. Both are undesirable. In addition, a copying machine using the contact transmission-type exposure device has the significant disadvantage that it cannot be used to copy an original having characters or patterns on both sides, because the characters or patterns on the two sides of the original would both be copied as if they were both on one side.
In order to form the electrostatic latent image of an original on a photosensitive surface in a conventional electrophotography device, the original's surface is illuminated with an external light source such as a lamp. The light reflected therefrom is applied through a lens or the like to the photosensitive surface which has been uniformly charged. That is, it is essential for the device to have optical means for illuminating the surface of an original, and therefore the device is unavoidably bulky.
A means for forming the electrostatic latent images of both sides of an original on two photosensitive surfaces simultaneously have never been proposed in the art.